The speed of a hydraulic system is determined by the amount of flow delivered.

The power produced by a hydraulic motor is determined by the flow and pressure drop of the motor. The displacement and pressure drop of the motor determines the torque it generates.

Working pressure affects operating torque, speed, flow, and horsepower of the motor. The operating speed is the speed at which the hydraulic motors’ moving parts rotate.

Actual output delivered by the hydraulic motor is less than theoretical torque because of the mechanical frictional losses like bearing losses etc.

Either of two basic methods are used for controlling the speed of a hydraulic motor. First, a variable-displacement pump controls flow to the motor. This configuartion is commonly known as a hydrostatic transmission.

Friction between mating parts affects the mechanical efficiency of a hydraulic motor. Gear motors typically have an overall efficiency of 70–75% as compared to vane motors which have 75– 85% and piston motors having 85–95%.

Tests carried out on a 44 megawatt 6-pole synchronous ABB motor shortly before delivery showed an efficiency 0.25 percent greater than the 98.8 percent stipulated in the contract, resulting in the world record for electric motor efficiency.

When choosing a motor for a centrifugal pump, you must consider the impeller size, maximum capacity, specific gravity of the fluid, and service application in case API requirements apply. If you take these things into account, you will select the right motor for your centrifugal pump application.

Most pump motors are supplied with a 1.15 service factor and, in an ideal situation, a 10HP model can be loaded to 11.5HP. Standard single phase motors are designed to operate on 230VAC while three phase models are usually wound for both 230 and 460VAC.

The applications of different DC motors are: DC shunt motor: It is an almost constant speed motor. Hence it is used for driving constant speed line shafts, lathes, centrifugal pumps, small printing presses, paper making machines, etc.

The NOL Horsepower is the maximum power value calculated in order to handle the maximum power demanded by the pump at any point along the curve. NOL Horsepower represents the amount of real horsepower going to the pump, not just the horsepower used by the motor.

Pump Power calculation Formula: Pump Power P(kW) = q(m3/hr) x ρ(kg/m3) x g(m2/s) x h(m) x p(Pa) / 3600000. The same way pump power in horsepower formula can be written as, Pump Power P(HP) = q(m3/hr) x ρ(kg/m3) x g(m2/s) x h(m) x p(Pa) / 2685600. Also above pump power is required to lift the liquid to head meters.

Pump Hydraulic Power (ph) = (D x Q x H x9. Pump Hydraulic Power (ph) = (1000 x 0.005 x 65 x9. 87)/1000 =3KW. Motor/ Pump Shaft Power (ps)= ph / pe = 3 / 80% = 4KW. Required Motor Size: ps / me =4 / 90% = 4.5 KW.